128 in Shank Dia, 1/2 in Washer Dia, For Use With: GCN-MEP and T3 Gas Actuated Nailers, Carbon Steel Washer Fastener, Galvanized, Material Fastened To: Concrete, Concrete Filled Deck and Masonry.Simpson Strong-Tie Drive Pin, Single Shot Step Shank, Series: GW Series, 1/2 in Shank Length, 0.11 in, 0.3 in Head Dia, 0.